30 Overheating Electronics and Corrective Steps to Take

In A/C and process applications, the problems of bypassing, recirculation, or small flow areas (obstruction to flow) occur all too frequently (Chapters 19 and 20). Similar problems occur in racks and screen rooms. The corrections needed may be difficult to attain because the cooling supplied by the A/C system must be delivered in engineered systems (screen room and racks serving as ducts, and blowers placed where needed) over which the A/C supplier has no control. Those that assemble equipment in racks seldom have a heat transfer engineer available. Even if available, electronics engineers would seldom allow a change in the electronic system when the odds are 85% to 15% that their design will work with a good blower(s) selection.

Racks with large cooling loads require more cooling air than those with lesser requirements. Electronics engineers select the equipment that defines the cooling load. An input often overlooked is that of the duct designer. Ducts, or their equivalent, are necessary to carry the cool air from the A/C unit to racks where the heat of electronics is removed. Duct calculations are rarely made. Yet, the corrective measure is almost always to modify the duct system in some fashion. Ignoring duct engineering is the cause of most electronics failures. It is not surprising that duct problems are not addressed by the A/C supplier as their responsibility ends at the connections to their equipment.